BURLINGTON — A Vermont police officer who had his nose broken and suffered a concussion after a mentally ill man hit him in the head pleaded not guilty Thursday to criminal charges of shooting the man on a Winooski street.

Winooski Cpl. Jason Nokes initially told state police investigators that he thought the man who had assaulted him was carrying a knife, but he later admitted he never saw a weapon, court documents said.

Nokes, 42, of Milton, was released after he entered the pleas to charges of aggravated assault, reckless endangerment and providing false information to state police when they conducted the independent investigation.

The Burlington Free Press reported that more than two dozen off-duty police and correctional officers attended the arraignment in apparent support for Nokes, a 19-year police veteran.

Nokes had no comment after the hearing.

The April 25 encounter began when Isaac Sage, 35, of Winooski, refused to leave a private gym.

Court documents say Sage assaulted Nokes on the street after Nokes tried to handcuff him. Nokes shot Sage in the leg while another officer was trying to subdue Sage.

Sage was not seriously injured. Charges against Sage were dismissed after he was found incompetent to stand trial.

Chittenden County State’s Attorney T.J. Donovan said that the case centers on Nokes’ claim Sage had a knife.

“He was knowingly giving false information to a law enforcement officer for the purpose of deflecting the investigation from his actions and was attempting to provide further justification for shooting Sage,” according to an affidavit by Vermont State Police Sgt. Jacob Zorn.